Note: Descriptions are shown in the official language in which they were submitted.
CA 02412684 2002-11-25
-1- F:_tor.:ey Pocket No. 67343
APPARATUS FOR MANUFACTURING
FLEXIBLE PACKAGES HAVING SLIDE CLOSURES
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention pertains to the
manufacture of flexible packages, such as plastic bags,
and in particular to packages having fastener closures
employing sliders.
2. Description Of The Related Art
With the recent emphasis in providing consumers
with bulk quantities of various commodities, such as food
products, reclesabl.e packages have become increasingly
popular. One of the most popular means of providing
reclosability is to employ zippers of various types,
particularly zippers which are compatible with flexible
packages of plastic filrr construction. Manufacturers of
food products and other commodities are concerned with
filling the contents of a flexible package as quickly and
economically as possible. It is important that the
opening provided by the fastener be made as large as
practically possible. Consumers or other end users also
prefer large sizes openings for easy extraction of
products from the package interior. Even with large
openings, however, products within the package may
interfere with fastener operation when product poured or
CA 02412684 2002-11-25
-2- Attorney Docket No. 67343
otherwise dispensed from the package becomes entrained in
the fastener components.
Other improvements to flexible reclosable
packages are being sought. For example, when handling
products comprised of numerous small pieces, such as
shredded cheese or cereal, for example, it is generally
desirable to have the package formed into a pouch which
is open at one end, or along one side, so as to allow
product to be poured or shaken through the reclosable
opening. It is desirable that the product be allowed to
freely flow past the reclosable opening. Preferably, the
path taken by the product within the package should be
made as smooth as possible.
Although improvements have been made in the art
of plastic welding and joining, manufacturers of consumer
products employing high speed production techniques are
continually seeking improved package forming methods and
equipment.
SUMMARY OF THE INVENTION
It is an object of the invention to provide
apparatus for manufacturing improved, shrouded and
unshrouded flexible packages.
Another object of the invention is to provide
apparatus for making reclosable packages having fastener
sliders which are protected as the package contents are
poured out or otherwise extracted.
A further object of the invention is to provide
apparatus for making a reclosable plastic package having a
slider fastener with improved containment of the slider in
a manner which also optimizes the size of the bag opening.
A further object of the invention is to provide
apparatus for making a plastic bag having a slider
fastener with an improved end "crush" stop of the fastener
tracks.
CA 02412684 2002-11-25
-3- Attorney Docket No. 67343
These and other cbjects of the invention are
provided in a horizontal form-fill. seal machine for
combined in-line and rotational manufacturing of food
packages that have a shrouded mated fastener tracks with
slider closures, that comprise a supply of web material
which extends in an in-line machine direction and defines
a serial succession of package sidewalls and extends in
the machine direction. A supply of mated fastener tracks,
that includes a first track with a shorter flange mated to
a second track with a longer flange. A fold member that
receives the web material. A web drive that transports
web material over -fold member in the in-line machine
direction, and folds web material into overlying side-by-
side portions, one against the other, to form a continuous
succession of folded package portions that extends in the
machine direction and has pairs of overlying first and
second package sidewalls that have overlying free edges
with shroud portions at the free edges. A slider member
mateable with mated fastener tracks for movement along
mated fastener tracks in opposite directions to open and
close mated fastener tracks. A slider installation member
inserting slider member onto mated fastener tracks.
Fastener seal bars extending in the machine direction,
sealing a portion of each flange of fastener tracks to
first sidewall., leaving the flanges free to attach to the
second package sidewall. Side seal bars extending at an
angle to machine direction, sealing portions of a package
sidewall together to form respective side seals of the
food package. A filler member filling product into a
package. A sidewall sealing member sealing second package
sidewall to second track flange. A shroud seal member
that seals the free edges of the package sidewalls to form
a shroud that enclose::, the fastener tracks, to form a
completed food package. A turntable member mounted filler
member, side wall seal member and shroud seal member for
CA 02412684 2002-11-25
-4- Attorney Docket No. 67343
movement in a rotational direction, and a transfer station
mounted on the turntable for transferring completed food
package away from the machine.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a fragmentary front elevational view
of a flexible package according to principles of the
present invention;
FIG. 2 is a fragmentary cross-sectional view
taken along the line 2-2 of FIG. 1;
FIG. 3 is a fragmentary end view indicated by
line 3-3 of FIG. 1;
FIG. 4 is fragmentary front elevational view
showing construction of the flexible package;
i5 FIG. 5 is a top plan view of the slider member;
FIG. 6 is a front elevational view thereof;
FIG. 7 is an elevational view from one end
thereof;
FIG. 8 is an elevational view from the other end
thereof;
FIG. 9 is an end view of a fastener track sub-
assembly;
FIG. 10 is a cross-sectional view, in schematic
form, taken along the line 10-10 of FIG. 1 with the slider
moved to the left;
FIG. 10a is a fragmentary view, of FIG. 10 shown
on an enlarged scale;
FIGS. 10b and lOc show alternative seal
constructions;
FIG. 11 is a fragmentary front elevational view
showing contents being poured from the flexible package;
FIG. 12 is a fragmentary front elevational view
showing contents of a prior art package;
CA 02412684 2002-11-25
-5- Attorney Docket No. 67343
FIG.13 is a fragmentary front elevational view
of another flexible package according to principles of the
present invention;
FIG. 14 is a front elevational view of another
flexible package according to principles of the present
invention;
FIG. 15 is a fragmentary elevational view of a
shrouded flexible package constructed according to
principles of the present invention;
FIG. 16 is a fragmentary cross-sectional view
taken along line 16-16 of FIG. 15;
FIG. 17 is a fragmentary end view of the package
of FIG. 15;
FIG. 18 is a fragmentary elevational view of a
further embodiment of a flexible package constructed
according to principles of the present invention;
FIG. 19 is a fragmentary elevational view of
another embodiment of a shrouded flexible package;
FIG. 20 is a cross-sectional view taken along
the line 20-20 of FIG. 15;
FIG. 21 is a cross-sectional view similar to
that of FIG. 20, shown with the schematic depiction of
tooling to form the flexible package;
FIG. 22 is a fragmentary elevational view of a
further embodiment of a shrouded flexible package;
FIG. 23 is a fragmentary elevational view of an
additional embodiment of a shrouded flexible package;
FIG. 24 is a cross-sectional view similar to
that of FIG. 20 but showing an alternative shroud
construction;
FIG. 25 is a fragmentary elevational view of a
further embodiment of a shrouded flexible package;
FIG. 26 is a perspective view of apparatus for
constructing flexible packages according to principles of
the present invention;
CA 02412684 2002-11-25
-6- Attorney Docket No. 67343
FIG. 2% is a side elevational view thereof;
FIG. 2c is a fragmentary view showing the
plastic web;
FIG. 29 shows the plastic web being folded;
FIG. 30 shows a portion of FIG. 29 taken on an
enlarged scale;
FIG. 31 is a fragmentary view of the lower right
corner of FIG. 30, taken on an enlarged scale;
FIG. 32 shows an operation performed on the
bottom of the web portions;
FIG. 33 shows an alternative construction;
FIG. 34 shows end stop and slider work stations
of FIG. 26, taken on an enlarged scale;
FIG. 35 is a cross-sectional view taken along
the line 35-35 of FIG. 30;
FIG. 36 is a cross-sectional view taken along
the line 36-36 of FIG. 30;
FIG. 37 shows a vertical sealing work station
portion of FIG. 26;
FIG. 38 shows a portion thereof on an enlarged
scale;
FIG. 39 shows an example of a flexible package
constructed with apparatus according to principles of the
present invention;
FIGS. 40a and 40b show the severing work station
of FIG. 26, on an enlarged scale;
FIG. 41 is a perspective view showing filling of
a flexible package;
FIG. 42 is a side elevational view thereof;
FIG. 43 is a top plan view thereof;
FIG. 44 is a diagrammatic view of FIG. 42,
FIG. 45 shows a top sealing work station of FIG.
26;
FIG. 46 is a cross-sectional view taken along
the line 46-46 of FIG. 45;
CA 02412684 2002-11-25
-7- Attorney Docket No. 67343
FIG. 47 is a cross-sectional view taken along
the line 47-47 of FIG. 39;
FIG. 48 shows the bag opening station of FIG.
26, taken on an enlarged scale;
FIG. 49 shows the opening and pre-flushing
station of FIG. 26, taken on an enlarged scale;
FIG. 50 shows a cross-sectional view taken along
the line 50-50 of FIG. 49 with the opening member shown
fully inserted in the flexible package;
FIG. 51 shows a post-filling gas flushing
operation; and
FIG. 52 shows the transfer station of FIG. 26 on
an enlarged scale.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
i5 Referring now to the drawings and initially to
FIGS. 1-8, an improved flexible package is generally
indicated at 10. The terms "package" and "bag," are used
interchangeably and are not intended to refer to any
relative size of the finished item.
Flexible package 10 preferably comprises a
plastic bag having front and back panels 12, 14 joined
together at the left end by a side seal 20 and at the
right end by a side seal 22. Side seal 20 is preferably
of conventional conduction heat-sealed construction,
having a generally constant width throughout. If desired,
side seal 20 can be employed on both sides of the flexible
package. Panels 12, 14 are further joined together at
their bottom ends by a bottom seal 24 (see FIG. 10)
extending between side seals 20, 22, as is known in the
art. Alternatively, the bottom seal can be replaced by a
fold line with panels 12, 14 being formed from a
continuous sheet of plastic material.
The upper end of flexible package 10 features a
reclosable opening including a slide fastener arrangement
CA 02412684 2010-03-08
-8-
with fastener tracks 26, 28 and a slider 30, all
preferably of polyolefin material. The slider 30'is
slidable along the fastener tracks, causing the fastener
tracks to interlock or mate (as shown in FIG. 2) for
closure of the flexible package and to unmate or separate
to open the flexible package for access to contents in the
package interior. As will be seen herein, features
associated with the fastener slider arrangement allow an
unprecedented enlarged opening of the flexible package.
The enlarged package opening made possible by the present
invention benefits manufacturers filling the package, as
well as consumers dispensing product from the interior of
the flexible package. In the preferred embodiment shown,
the fastener tracks are also referred to as "zipper"
tracks.
The flexible package according to principles of
the present invention has found immediate commercial
acceptance for use with food products, including
perishable food products, such as cheese. Accordingly, it
is generally preferred that the flexible package includes
a hermetic seal 36 in the form of a peelable seal as
taught in commonly assigned United States Patent Nos.
5,014,856; 5,107,658 and 5,050,736,
As mentioned above, flexible package 10
preferably comprises a bag having panels 12, 14 formed
from plastic sheet material. The sheet material can be of
a single material type, such as polyolefin materials
including polyethylene and polypropylene, but preferably
comprises a laminate assembly of several different
material types, as is known in the art to provide a
barrier to moisture as well as certain gases, such as
oxygen or inert fillers of the types used with food
products. Other types of laminate films, such as those
CA 02412684 2002-11-25
-9- Attorney Docket No. 67343
known in the art to preserve food freshness, may be
employed. Where the contents of the flexible package are
not perishable or where other considerations may dictate,
the panels 12, 14 can be constructed without regard to gas
or vapor barrier properties. FIGS. 2 and 3 indicate that
it is generally preferred that the fastener tracks be
joined to web--like flanges which, in turn, are joined to
panels 12, 14 as will be described below with reference to
FIG. 10.
Referring now to FIGS. 5-8, fastener slider 30
has a top wall 44, a shorter side wall 46 and a longer
side wall 48, cooperating to define an internal cavity 50
for receiving the fastener tracks 26, 28. As can be seen
by comparing the end views of FIGS. 7 and 8, a first end
54 of the slider defines a cavity which is generally
rectangular. The opposed end 56 (shown in FIG. 8) defines
a cavity which is generally arrowhead or A-shaped, as
indicated by -reference numeral 50b, conforming to the
outline of the interlocked fastener tracks shown in FIG.
2. When the slider 30 of FIG. 1 is moved to the right,
end 56 is at the leading end of the slider and the
fastener tracks 26, 28 are unlocked, thus opening the
flexible package 10. Conversely, as slider 30 of FIG. 1
is moved to the left, end 54 (shown in FIG. 7) is made the
leading end, and fastener tracks 26, 28 are interlocked in
the manner indicated in FIG. 2, to close the flexible
package.
Referring again to FIGS. 2, 7 and 8, a number of
features cooperate to maintain slider 30 captive on
fastener tracks 26, 28. As can be seen for example in
FIG. 8, a pair of upwardly facing stepped portions 62 are
formed on either s=ide of the slider cavity. Inwardly
extending protrusions 64 are located at the other end of
the slider. Protrusions 64 and stepped portions 62 engage
the bottoms 26a and 28a (see FIG. 2) of fastener tracks
CA 02412684 2002-11-25
-10- Attorney Docket No. 67343
26, 28, as can be seen for example in FIG. 10. The
engagement of the stepped portions 62 and the protrusions
64 with the bottoms of the fastener tracks prevents the
slider from beinq upwardly dislocated from the fastener
tracks.
Referring to FIGS. .1, 3 and 13, the ends of the
fastener tracks are deformed or "crushed" to form stops
68. Preferably, stops 68 are formed by the application of
ultrasonically generated heat and pressure to the ends of
fastener tracks 26, 28. It has been found that the use of
present day conduction heat sealing techniques does not
provide the control needed to attain the intricate, close
tolerance design of stop members according to principles
of the present invention. Further, it has been found that
the use of present day conduction heat sealing techniques
immediately adjacent previously formed stop members tends
to distort the stop members, oftentimes to an extent
rendering the stop members unacceptable from a quality
control standpoint. As will be seen herein, stops 68 are
configured for maximum efficiency, having the smallest
front elevational surface area (i.e., the surface area
visible in FIGS. 1 and 1>, for example), which is adequate
for containing slider 30 on the fastener tracks.
Referring to FIG. 3, the sides of the fastener
tracks are softened and compressed at stop faces or sides
72 so as to impart a pre-selected width w and an upwelling
displacement a above the upper surfaces 26b, 28b of
fastener tracks 26, 28 (see FIG. 2). The material
displaced above the upper surface of the fastener tracks
interferes with the top wall 44 and ends of slider 30 to
limit its sideways travel.
With reference to FIG. 3, the slider stop 68
(that is, the deformed portion of fastener tracks 26, 28)
is carefully configured so as to avoid deformation of the
bottom surfaces 26a, 28a of the fastener tracks. With
CA 02412684 2002-11-25
-11- Attorney Docket No. 67343
reference to FIG. 1, the lower ends of the fastener tracks
extend undeformed, substantially to the side edges 16, 18
of the flexible package 10. FIG. 1 shows slider 30
"parked" at a fully opened position, with end 56
contacting the stop 68 located at the right hand end 22 of
the flexible package. Stop members 68 and the undisturbed
bottom surfaces 26a, 28a of the fastener tracks in the
area of stop members 68 cooperate to captivate slider 30
on the fastener tracks, preventing its unintentional
removal from flexible package 10.
It is preferred that the bottom edges 26a, 28a
remain undeformed also for that portion extending beyond
slider 30, and underneath at least a portion of the right
hand stop 68. With reference to Fig.3, a gap g is formed
between the bottom edges of the fastener tracks and the
top portion 81 of side seal 22. As can be clearly seen in
FIG. 3, the stop 68, formed by ultrasonic techniques, is
separated by a substantial distance from the side seal,
which is typically formed using conduction heat seal
techniques found to be incompatible with the precise, high
resolution ultrasonic techniques used to form stop 68. A
second stop 68 formed at the left hand end 16 of flexible
package 19 is constructed in a similar fashion and extends
beyond the end 54 of slider 30 when the slider is moved
fully to the left, closing the upper end of the flexible
package. As will be explained in greater detail herein,
separation of the "crush" operation performed on the
fastener tracks to form stops 68 from the conduction heat
sealing operation to form the enlarged side seals, allows
stops 68 to take on a reduced size, effectively extending
the size of the package opening, without sacrificing
ability of the stops to effectively retain slider 30 on
the fastener tracks.
Referring to FIGS. 1 and 4, side seal 22
includes an upper enlarged or tapered portion 80 having a
CA 02412684 2002-11-25
-12- Attorney Docket No. 67343
width substantially greater than the lower end of side
seal 22, sufficient to underlie the substantial entirety
of slider 30 when the slider is fully moved to the
"parked" position as shown in FIG. 1. The width of the
enlarged, tapered portion 80 ranges between 200% and 400%
(or more for very narrow side seals, e.g., 2 mm or less)
of the width s of side sea_: 22 and most preferably ranges
between 250% and 3001 of the side seal width s.
The enlarged, tapered end 80 of side seal 22 has
a S-shaped or double re-entrant bend contour 84 which
partly defines the package interior. With reference to
FIG. 11, the curved edge 84 of the enlarged side seal
portion 80 provides a smooth transition at the corner of
the package opening, preventing product entrapment within
the flexible package. As those skilled in the art will
appreciate, the smooth transition at the opening corner is
especially beneficial for flexible packages, where shaking
techniques otherwise suitable for rigid packages, are
rendered largely ineffective by flexible panels 12, 14 and
especially panels of very thin, unsupported material which
are likely to collapse in use.
The smooth transition provided by curved edge 84
also deflects or guides product 86 away from slider 30 as
product is poured or otherwise removed from flexible
package 10. This prevents contamination of mating
surfaces of the slider and the fastener tracks, which
would otherwise deteriorate the ability of slider 30 to
move freely, performing interlocking and unlocking of the
fastener tracks. As indicated in FIG. 12, in prior art
arrangements product 86 is allowed to freely contact the
bottom end of slider 30, a condition which is avoided by
flexible packages according to principles of the present
invention.
Preferably, fastener tracks 26, 28 are `crushed"
to form stop member 68, using conventional ultrasonic
CA 02412684 2002-11-25
-13- Attorney Docket No. 67343
heating equipment: which allows for a highly accurate
shaping of the stop member as well as withdrawal of the
deformation area away from the bottom surfaces 26a, 28a as
shown, for example, in FIG. 3. As can be seen for example
in FIG. 1, the width of stop member 68 is considerably
less than the enLargFd tapered portion 80 of side seal 22,
and preferably in of a smaller width than that of the
narrower major portion of side seal 22. With reference to
FIG. 1, the width d of stop member 68 is less than the
width s of side seal 22. Preferably, stop member width d
ranges between 50% and 200% of the width s of side seal
22. Preferably, the width w of the stop member 68 (i.e.,
the "crush" dimension) ranges between 25% and 80% of the
width z of the fastener tracks, as illustrated in FIG. 3.
The amount of upward displacement or upwelling u is
approximately at least as great as the thickness of upper
wall 44. It should be kept in mind that the total mass of
the stop must be sufficient to hold the slider captive.
The stop member 68, in addition to having a
reduced width d in front elevational view and a small
width w in end view (see FIG. 3), has a sufficiently
smaller mass and frontal surface area than stops employed
in the prior art. This construction allows the slider 30
to be moved to an extreme position immediately adjacent
the edge 22 of flexible package 10, thus maximizing the
package opening, allowing for easier removal of the
package contents. This reduced size of stop 68 also
contributes to the precision of the ultrasonic heating and
formation of the stop member, needed to attain required
precise dimensions. Further, from a manufacturing
standpoint, the dwell time to melt and shape the stop 68
is substantially reduced, contributing to the overall
efficiency for the package manufacturer.
Prior art stop members have been formed by
"crushing" the entire fastener profile, including the
CA 02412684 2002-11-25
-14- Attorney Docket No. 67343
bottom surfaces 26a, 28a. In addition, even if ultrasonic
techniques are employed for the stop member, prior art
side seals (formed using conduction heat seal techniques
and much larger, eftentimes three to four times larger
than side seals according to the present invention) were
typically overlaid with the stop, contributing to a
substantial distortion of the stop structure. Even if the
prior art side seals were made to stop short of the
fastener tracks, the relatively high level of conduction
heating in the immediate proximity of the stop have been
found to cause a distortion of the stop, degrading control
over its size and shape. These disadvantages are avoided
with practice of the present invention, where the small,
compact size of the stop is employed, and the gap g is
formed between undeformed fastener bottom surfaces 26a,
28a and the enlarged seal portion 80.
Turning now to FIGS. 4, 9 and 10, and initially
to FIG. 9, the fastener tracks are preferably formed from
a sub-assembly generally indicated at 70 in which the
fastener tracks 26, 28 are provided with corresponding
fastener flanges 72, 74. The fastener flanges 72, 74 are
coextensive with the fastener tracks 26, 28 and take the
form of a plastic web to be heat sealed to the panels 12,
14. As can be seen in FIG. 9, fastener flange 74 is
shorter in height than fastener flange 72, so as to
accommodate the preferred hermetic seal arrangement shown
in FIG. 10.
The fastener flanges 72, 74 are heat sealed to
panels 12, 14. With reference to FIGS. 4 and 10, fastener
flange 72 is welded or otherwise mechanically sealed to
panel 12 at weld band 78. As shown at the upper portion
of FIG. 10, the upper ends of panels 12, 14 are joined to
the outer outwardly facing surfaces of fastener flanges
72, 74 at points intermediate the fastener tracks and
peelable seal 36. Band 36 preferably comprises a hermetic
CA 02412684 2002-11-25
-15- Attorney Docket No. 67343
peelable seal formed by the joinder of panel 14 to the
inside face 72a of fastener flange 72 (see FIGS. 10 and
10a). Panel 1.2 is sealed to the opposite outside face of
the fastener flange as schematically indicated in FIG. 10.
In FIG. l0a the components of the peelable seal 36 are
shown, with film 1.2, which plays no part in the preferred
peelable seal, being shown in phantom.
Variations of the peelable seal are also
contemplated by the present invention. For example, in
FIG. 10b, the flanges 72, 74 of the fastener arrangement
are joined with a peelable seal. The upper ends of these
flanges are heat sealed to panels 12, 14 as shown. In
FIG. 10c a further alternative is shown with the peelable
seal 36 being formed at. the joinder of lower portions of
panels 12, 14. The upper portions of panels 12, 14 are
heat sealed to fastener flanges 72, 74.
As will now be appreciated, the enlarged,
tapered end portions 80 of side seal 22 cooperate with
other features of flexible package 10 to provide a number
of important advantages. More specifically, the enlarged
tapered end portions 80 provide a smooth transition of the
interior of flexible package 10 preventing product
entrapment in the slider and fastener track surfaces when
product is poured or otherwise dispensed. In addition,
the enlarged tapered portion 80 helps to secure slider 30
about tracks 26, 28 by maintaining a clearance from bottom
surfaces 26a, 28a of the fastener tracks. Further, the
enlarged tapered portions 80 of side seals 22 strengthen
and rigidify edge portions of panels 12, 14 in the
immediate area of the parked position of slide 30.
Often, the greatest amount of force applied by
the user to slider 30 occurs at the closing of the slider,
when the fastener tracks are unlocked or separated from
one another. When the slider 30 is in the middle of its
travel along the fasrener tracks, the user is provided
CA 02412684 2002-11-25
-16- Attorney Docket No. 67343
with a sensation of the proper direction of slider
movement. However, when the slider 30 is in the parked
position, and especially in the "parked open" position
shown in FIG. 1, the user's initial application of force
may be misdirected. The enlarged tapered portion 80
provides added stiffness and rigidity to the flexible
package at the initial point where pressure is applied to
the slider, thus further contributing to the assurance
that secure engagement will be maintained between slider
30 and the tracks 26, 28.
With reference to FIG. 4, a consumer desiring to
close the flexible package will grasp the enlarged side
seal portion 80, pulling in the direction of arrow 81
while pulling or pushing slider 30 in the direction of
arrow 31. The added stiffness and rigidity offered by
enlarged side seal portion 80 is provided at a point of
optimal effectiveness to react in an appropriate manner to
forces applied to slider 30 and to overcome any resistance
of the tracks 24, 26 to resume a mating, interlocked
condition as the fastener tracks are interlocked. Those
skilled in the art will appreciate that the "rolling
resistance" or dynamic resistance to movement of slider 30
is oftentimes lower than the initial static resistance,
opposing movement of the slider away from the fully opened
parked position shown, for example, in FIG. 4.
The added stiffness and rigidity imparted to the
flexible package 1.0 and especially panels 12, 14 by
enlarged side seal. portion 80 results in other advantages
when lightweight panels 12, 14 are employed. For example,
panels of the single polyolefin type where no laminate
film (such as PET or NYLON) is used to stiffen and support
the support panel, have oftentimes excluded the use of
sliding zippers, since minimum stiffness and rigidity
needed to operate a fastener slider was not available.
However, with enlarged side seal portions according to
CA 02412684 2002-11-25
--17- Attorney Docket No. 67343
principles of the present invention, adequate stiffness is
provided, even for lightweight, so-called "single" films.
As indicated in FIG. 10, flanges 72, 74 are
joined to respective panels 12, 14, preferably at their
lower ends, so as to prevent product from entering between
flange 72 and panel 12, as well as between flange 74 and
panel 14. In certain applications this may not be a
critical requirement. In FIG. 10, the upper portion of
panel 12 is shown for illustrative purposes as spaced from
the lower end of flange 72. In practice, it is generally
preferred that this spacing be eliminated, with panel 12
being in intimate contact with flange 72. Similarly, any
gap between panel 14 and the lower end of fastener flange
74 is preferably eliminated. Although it is most
preferred that the peelable seal be formed by joining
panel 14 to fastener flange 72, the peelable seal,
preferably a hermetic seal, can be formed between the
fastener flanges 72, 74 or directly between the panels 12,
14, although these alternative constructions are less
preferred than the arrangement shown in FIG. 10.
Turning now to FIG. 13, flexible package 10 is
shown constructed with the panels 12, 14, side seal 22,
upper enlarged side seal portion 80 and fastener tracks
26, 28, as described above.. The fastener tracks 26, 28
are preferably joined to flanges 72, 74 (not visible in
FIG. 13). FIG. 13 schematically illustrates commercial
fabrication of flexible package 10. As will be
appreciated by those skilled in the art, practical
commercial assembly requires recognition of tolerances of
the equipment and materials used to construct a viable
commercial product. For example, tracks 26, 28 are
ultimately mechanically coupled to panels 12, 14 using
conduction heat seal tooling. A gap 110 shown in FIG. 13
represents the tolerance range or margin of error for tool
alignment used to secure the fastener tracks 26, 28. As
CA 02412684 2002-11-25
-18- Attorney Docket No. 67343
mentioned, it is preferred that the upper end of enlarged
side seal portion 80 be spaced below the lower ends of the
fastener tracks, such as the lower end 26a of fastener
track 26 visible in FTC,. 13. Further, it is preferred
that the gap g continue beyond the end 56 of slider 30.
A gap 116 represents a tolerance range or margin
of error for the desired positioning of the upper end of
enlarged side seal portion 80, to provide clearance for
the bottom edge of slider 30. As illustrated in FIG. 13,
the upper end of enlarged side seal portion 80 falls at an
outermost limit of its tolerance range. Preferably, the
upper end of enlarged side seal portion 80 is within the
gap 116, rather than to one end thereof. The gap 116 also
accounts for any cant.. or angular mis-positioning or mis-
alignment where the upper end of side seal 80 may be
angled slightly from a position parallel to the fastener
tracks, as may be encountered in a practical commercial
environment.
A band 120 shown in FIG. 13 represents a
conduction heat seal of the fastener flange to the panels
12 or 14. This conduction heat seal 120 provides the
principal mechanical attachment of the fastener track
assembly to the package panels. Band 36 is the peelable
seal, preferably a hermetic seal, between panel 14 and
fastener flange 72. A gap 124 represents the desired
production spacing between production seal 120 and
peelable seal 36. The remaining band 128 represents the
production tolerance range or margin of error for
positioning of peelable seal 36 with respect to the
package panels.
In one commercial embodiment, flexible package
1.0 comprises a plastic bag having a width of approximately
6.5 inches from side edge to side edge and a total overall
height of approximately 10.75 inches. The fastener tracks
26, 28 have a height of approximately 4 millimeters, with
CA 02412684 2002-11-25
--19- Attorney Docket No. 67343
gaps 110, 116 each having a height of 2 millimeters. As
shown in the upper right hand corner of FIG. 13, stop 68
projects a distance u above the top edge of the fastener
tracks. In FIG. 13, only the top edge 26b is visible.
With reference to FIG. 1.0, the upper ends of panels 12, 14
are preferably spaced a distance p from the bottom edges
of the fastener tracks, ranging between 2 and 3
millimeters. The conduction heat seal 120 and the
peelable seal 36 each have a height of 6 millimeters, and
gap 124 located between the two, has a height of 2
millimeters. The desired spacing between conduction heat
seal 120 and peelable seal 36 has a maximum value of 2
millimeters and a minimum value required to prevent
overlap of the conduction heat seal and peelable seal.
The side seal 22 has a width ranging between 3 and 8
millimeters and the stop 68 has a width (see reference
character d in FIG. i.) ranging between 2.0 and 8.0 mm. As
can be seen with reference to FIG. 13, the upper end of
side seal 22 is spaced a substantial distance below the
upper edge of the flexible package. This spacing ranges
between a minimum value equal to the combined height of
the fastener tracks and gap 110, and a maximum value equal
to the combined height of the fastener tracks, gap 110 and
gap 116.
Referring to FIG. 14, several alternative
features are shown with reference to a flexible package
130. The right hand portion of flexible package 130 is
identical to flexible package 10, described above, except
for the addition of a peg hole 132 formed in the enlarged
side seal portion 80. Flexible package 130 has a left
side seal 20 as described above with respect to FIG. 1.
However, in the flexible package 130, the upper end of
side seal 20 is enlarged at 138 in a manner similar to
that of enlarged side seal portion 80. An optional peg
hole 140 is formed in the enlarged side seal portion 1.38.
CA 02412684 2002-11-25
-20- Attorney Docket No. 67343
Although the peg holes 132, 140 are shown having a
circular shape, virtually any shape (e.g., oval) can be
used, as well. Peg holes 132, 140 can be formed by
punching before or after the side seals are fully formed,
it being preferred that the upper ends of the side seals
provide a complete sealing of the panels and other
components of the flexible package. It will be
appreciated by those skilled in the art that the holes add
heat relief to the enlarged side seal portion. This helps
preserve the uniformity of the tapered area and of the
dimensioning of gap g, as well as the uniformity of
shrinkage which helps control manufacture on a production
basis. If desired, the heat sealing die can be made
hollow in the region of the peg holes, even in the absence
of peg hole features to attain further heat relief
advantages. It may also be preferable in some instances
to form the peg hcles 132, 140 as part of the formation of
the side seals using, in effect, a thermal cutting or
thermal punching technique. With the inclusion of two peg
holes 132, 140, flexible package 130 can provide an
improved presentation of art work or other indicia carried
on the panels of the flexible package.
It is generally preferred that textual and
graphic information be oriented generally perpendicular to
the side edges of the flexible package. If only one peg
hole is provided, the package will tend to hang rotated in
a vertical plane, according to the distribution of product
within the flexible package. With support given to two
peg holes 132, 140, the flexible package is oriented in an
upright position, making it easier to read the text and
graphical information carried on the package. If desired,
the text and graphical information printed on the rear
panel can be inverted so that a consumer can "flip" the
package to inspect the rear panel, without having to
CA 02412684 2002-11-25
--21- Att=orney Docket No. 67343
remove the package from the support pegs passing through
peg holds 132, 140.
Although the package opening, fastener tracks
and related features are shown at the upper end of the
flexible package, the present invention is intended to
cover arrangements in which the opening and related
structure is provided on the side or bottom of the
flexible package.
Referring now to FIGS. 15-25 and initially to
FIG. 25, an improved package according to principles of
the present invention, is shown. Package 199 includes the
features of flexible package 10, described above and in
addition includes a shroud portion 204 extending above
line of weakness 208 formed in panels 12, 14. Line of
weakness 208 can be formed using available conventional
techniques, and is preferably formed, using laser scoring
techniques. Preferably, line of weakness 208 extends
across the width of flexible package 199, from one side
edge to the other. As shown in FIG. 25, line of weakness
208 extends to edge 18, located at side seal 22. If
desired, side seal 2 can be replaced by side seal 20.
Preferably, shroud 204 is made for easy tear-
away removal in an intuitive manual operation not
requiring special directions. Preferably, a notch 210 is
formed in edge 18, and is located slightly above stop 68.
An optional angled or diagonal line of weakness 212
extends from notch 210 to an opening 214 which surrounds
slider 30. Opening 214 is illustrated as a rectangle with
rounded corners. Opening 214 can however take on other
shapes, such as that of a circle or teardrop, for example.
Opening 214 relaxes the strain in the shroud portion of
the flexible package caused by relatively large-sized
slide members. It is preferred that the opening 214 be
formed in the web prior to joining with fastener tracks.
Accordingly, careful registration of the opening 214 is
CA 02412684 2002-11-25
-22- Attorney Docket No. 67343
needed to insure the desired finished flexible package is
produced.
Preferably, slider 30 is located at a fully
closed position along the fastener tracks and is
surrounded by opening 214 at the closed position. In
order to gain access to the package contents, a user
grasps the upper edge of shroud 204 causing an initially
tearing at notch 210. Tearing continues along diagonal
line 212 and enters opening 214, continuing along opening
214 to line 208. With continued tearing across the width
of package 199, the shroud 204 is removed, leaving a
package substantially similar to the packages described
above in FIGS. 1-14.
Referring again to FIG. 25, shroud 204 includes
an upper fin seal 220 and a side fin seal portion 222.
Preferably, the upper fin seal 220 inside fin seal 222 are
formed in separate sealing operations and are made to
slightly overlap one another for package integrity and
sealing of the package interior. The bottom of side fin
seal 222 is terminated at or slightly above end stop 68.
It is most preferred that side fin seal 222 be terminated
slightly above end stop 68 to avoid interfering with the
controlled formation of the end stop which, as pointed out
above, has a shape and position providing novel
advantages. Notch 210 in the preferred embodiment shown
in FIG. 25 is formed at the lower end of side fin seal
222. If desired, notch 210 could be formed in a gap
between end stop 68 and a side fin seal shortened with
respect to the side fin seal illustrated in FIG. 25.
Turning now to E'IGS. 15-18 a flexible package
230 is shown. Package 230 is substantially identical to
package 199 described above, except that opening 214 does
not directly communicate with diagonal line 212. Tearing
of package 230 to remove shroud 204 is initiated at notch
210 and continues along diagonal line 212 to a point of
CA 02412684 2002-11-25
-23- Attorney Docket No. 67343
intersection with line of weakness 208. If desired, the
portion of weakness line 208 designated by reference
numeral 232, line between diagonal line 212 and-edge 18
can be omitted, if desired. Further, weakening line 208
and diagonal line 212 can be formed in a single operation
using conventional techniques such as laser cutting. As a
further alternative, diagonal line 212 can be made to
curve either along its entire length, or at the point of
intersection with weakening line 208. FIG. 15 shows a
central peg hole 234 is formed in upper fin seal 220.
Referring now to FIG. 19, flexible package 240
is substantially identical to flexible package 230, except
for the omission of opening 214. Arrangement of FIG. 19
is preferably employed where the width of slider 30 is
reduced, or the shroud 204 is sufficiently flexible or has
an enlarged cross section so as to completely enclose
slider 30 without requiring an opening to relax tension in
the material forming the shroud.
Referring now to FIG. 20, a cross section of
flexible package 199 is shown. Preferably, shroud 204 is
formed as a continuous integral extension of panels 12,
14, the upper free edges of which are joined together to
form upper fin seal 220.
Referring Lo FIG. 21, exemplary tooling to form
the package 199 are shown. For example, a pair of upper
seal bars 250 form upper fin seal 220 while a pair of
intermediate seal bars 252 join panels 12, 14 to fastener
flanges 72, 74. Lower seal bars 254 form the peel seal 36
and weld band 78 (FIG. 20). The bottom of package 199, as
is preferred, with the other flexible packages shown
herein, is formed by a dead fold 258.
Referring now to FIG. 22, a flexible package 260
is substantially identical to flexible package 230 of FIG.
18, except for a curved line of weakness 264 joining notch
210 with weakening line 208.
CA 02412684 2002-11-25
-24- Attorney Docket No. 67343
FIG. 23 shows a flexible package 270 similar to
that of flexible package 230, except that a large or
tapered side seals are provided at each side of the
package. Peg holes 132, 140 are formed in the tapered
side seal portions and if desired an optionally central
peg hole 234 can be formed in upper fin seal portion 220.
As with the other embodiments shown herein, it is
generally preferred that the enlarged or tapered side seal
portions stop short of the line of weakness 208.
FIG. 24 is a cross-sectional view of an optional
flexible package 280 substantially identical to flexible
package 199, described above, except that a shroud member
282 is separately formed from panels 12, 14 and is joined
to the upper ends of the panels by conventional welding or
other joining techniques. Most preferably, shroud 282 is
joined to the upper ends of panels 12, 14 at the point of
sealing with flanges 72, 74. The weakening line for
removal of shroud of 282 can be formed either above or
below the point of sealing with remainder of the flexible
package.
It is generally preferred that textual and
graphic information De oriented generally perpendicular to
the side edges of the flexible package. If only one peg
hole is provided, the package will tend to hang rotated in
a vertical plane, according to the distribution of product
within the flexible package. With support given to two
peg holes 132, 1.40, the flexible package is oriented in an
upright position, making it easier to read the text and
graphical information carried on the package. If desired,
the text and graphical information printed on the rear
panel can be inverted so that a consumer can "flip" the
package to inspect the rear panel, without having to
remove the package from the support pegs passing through
peg holds 132, 140.
CA 02412684 2002-11-25
-25- Attorney Docket No. 67343
Although the package opening, fastener tracks
and related features are shown at the upper end of the
flexible package, the improved flexible package is
intended to cover arrangements in which the opening and
related structure is provided on the side or bottom of the
flexible package.
Turning now to FIG. 26 and following, apparatus
for manufacturing improved flexible packages having slide
closures will now be described. As will be seen herein,
the apparatus according to principles of the present
invention, generally indicated at 300 employs a horizontal
form fill seal arrangement with the in-line application of
mated fastener tracks to a folded web. And with a rotary
station generally indicated at 1000 for package filling
sealing and transfer. Apparatus 300 brings all of the
required packaging components together, for assembly, at
the point of fill.
Referring to FIGS. 26 and 27, apparatus 300
includes a web supply roll 304 providing a supply of web
material 306 preferably comprising a conventional plastic
packaging film. Web material 306 is advanced in the
direction of arrow 308. Punches 312 are schematically
indicated and form the openings 214 on opposed bag panel
portions 12, 14 (see FIG. 15). Also, indicated in FIG. 29
are diamond shape cutouts 324 formed by punches
schematically indicated in FIG. 26 at 312. In FIG. 28
line 318 indicates a crease or a fold line about which web
306 is folded about plow 330 (see FIG. 30) to form a "dead
fold" 320 at the bottom of the finished bag, as shown in
FIG. 29. The lines 326 running generally transverse of
web 206 indicate severing lines which divide one bag
portion from another, the bag portions preferably being
serially formed from a common web. After severing, the
diamond cutouts 324 become pairs of opposed tear notches
210 shown for example in FIG. 39.
CA 02412684 2010-03-08
-26-
As mentioned, the web is initially formed so as
to have a "dead fold" at its bottom end. If desired,
processing can continue, eventually producing separate
bags having dead fold bottoms. As a preferred
alternative, a gusset blade 340 can be employed in the
manner illustrated in FIG. 30 to form a gusset 342 in the
bottom of the folded web. A W-shaped gusset or pleated
bottom 342 is shown in greater detail in FIG. 31, and a
"Delta-fold" gusset is shown in FIG. 33. The pleated
bottoms 324 are sealed as indicated in FIG. 32 using
gusset sealing dies 326. The dies 326 include upstanding
saw tooth portions 328 configured to seal the corners at
side edges of the individual, separated bags.
Referring to FIGS. 26 and 30, a supply of mated
fastener track 210 (preferably comprising fastener tracks
26, 28 - see FIG. 2) is supplied on roll 350. Preferably,
the fastener tracks include respective mounting flanges
which overlie one another, and which extend along the
mated fastener tracks. As can be seen, the mounting
flanges are of unequal height (with the food package
viewed in an upright position) and extend from the
fastener tracks different amounts. Further details
concerning the construction and operation of the mated
fastener tracks 210 and slider 30 of the preferred
embodiment may be obtained with reference to United States
Patent No. 6,047,450,
With additional reference to FIGS. 26 and 34,
the mated fastener track 210 is fed through a roller
guides 354 to enter a work station generally indicated at
360 for forming stops 68 in the mated fastener track. An
adjacent work station 364 is provided for applying slide
members 30 to the fastener track.
Turning again to FIG. 26 and with additional
reference to FIG. 30, the prepared zipper track (with end
CA 02412684 2002-11-25
-27- Attorney Docket No. 67343
stops and slider membeers) and the folded web is brought
together at fastener sealing station 400. FIG. 35 shows a
cross section of the web and fastener track prior to
entering the sealing Station. As shown, web 306 is folded
into a general V-shape to form opposed front and rear
panels 402, 404 shown by a dead fold 406. The mated
fastener track includes mated male and female track
members 26, 28 as described above, for example, with
reference to FIG. 2. Track members 26, 28 include a
longer depending flange 12 and a shorter depending flange
14, respectively. The side 14a of flange 14 is joined to
the opposing interior surface 402a of panel 402, as will
be seen herein. Also, the lower surface portion 12a is
joined to panel surface 402a. The resulting joinder is
diagrammatically illustrated in FIG. 44. After filling
the flexible packag.7e, the outwardly facing surface
portions 12b and 12c are joined to the opposing interior
surface 404a of panel 404.
The initial sealing of the prepared fastener
track to the side wall panels is carried out at station
400, preferably using five sealing tools. With reference
to FIG. 36, four hor.zontal. sealing tools are arranged in
two pairs. The upper pair of sealing tools or dies
includes sealing die 410 adjacent panel 402 and sealing
die 412 adjacent panel 404. As will be seen herein, panel
402 preferably comprises the front panel of the flexible
package while panel 404 comprises the opposed, rear side
of the package. If desired, printing on the front and
rear panels 402, 404 could be interchanged one for the
other.
Flange 14 is welded or otherwise joined to panel
402, but the longer flange 12 remains unjoined to panel
404, to allow package filling as indicated in FIG. 44.
Accordingly, sealing tool 410 is heated to a temperature
sufficient to cause joining of flange 14 to panel 402.
CA 02412684 2002-11-25
--28- Attorney Docket No. 67343
Preferably, sealing i.a accomplished with the application
of pressure and accordingly sealing tool 412 is employed
as a back up to sealing tool 410. Preferably, both
sealing tools 410, 412 are advanced toward one another,
toward separator tool 416. At this stage of the assembly
operation, it is preferred that sealing tool 412 be
unheated, so as to prevent unwanted joinder of flange 12
to panel 404. In order to prevent inadvertent sealing of
fastener flanges 12, 14 by sealing tool 410, an unheated
or cooled separator tool 416 is temporarily placed between
flanges 12, 14. The joinder of the lower surface portion
12a of flange 12 and panel 402 forms a conventional peel
seal whereas the joinder of flange 14 to panel 402
comprises a permanent seal.
As mentioned, it is preferred that flange 12
remain free of joinder with panel 404. However, it is
desired that the lower portion of interior face 12a be
joined to panel 402. Accordingly, a pair of sealing tools
420, 422 are advanced toward one another to bring flange
face 12a in contact with the opposed interior surface 402a
of panel 402. Accordingly, sealing tool 420 is heated to
effect the desired joinder, but sealing tool 422 is either
cooled or unheated to prevent joinder of flange 12 to
panel 404.
Turning now to FIGS. 37 and 38, the joined web
and prepared fastener tracks are advanced to the station
430. With reference to FIG. 26, pairs of vertical sealing
bars 432 cooperate to form side seals for the flexible
package. With reference to FIG. 28, side seals are formed
along lines 326 and with reference to FIG. 39, for
example, the side seals are indicated by 20, 22. FIG. 39
shows a completed flexible package 200. Referring also to
FIG. 25, it can be seen that the side seals stop short of
end stop 68, so as to provide an intervening spacing. In
this manner, unwanted deformation of the end stop is
CA 02412684 2002-11-25
-29- Attorney Docket No. 67343
avoided as the side seals are formed. Accordingly, the
vertical sealing bars 432 are foreshortened with respect
to the overall height of the flexible package.
In the preferred embodiment, sealing bars 432
have heat loadings optimized for rapid assembly.
Accordingly, it has been found desirable to add vertical
cooling bars 434 at a downstream position to withdraw heat
from the side seals. As mentioned above, the vertical
sealing bars are foreshortened with respect to the overall
height of the flexible package. The vertical cooling bars
could also be foreshortened in a similar manner, since
their function is to withdraw excess heat lingering after
fusion of the side seals is completed. Alternatively, the
cooling bars can extend upward beyond the side seals, if
desired. If desired, additional operations such as
operating on the side panels with punches 438 while the
bag chain is temporarily stopped at station 430. Punches
438 are preferably employed to clear plugs from the
package tops, but can also be employed, for example, to
form side holes 132, 140 as shown in FIG. 14 or center
hole 234 as shown, for example, in FIG. 15. If desired,
the punching operation or other operations on the bag
panels can be carried out at station 450 located
immediately downstream of station 430.
The lower portions of the flexible packages or
bags are now fully formed except for being connected
together in serial succession in the form of a bag chain
or series of folded package portions. Top filling and
final sealing of the upper end of the flexible packages
remains to be accomplished. If desired, the filling and
final, top sealing could be performed with the flexible
packages serially connected in a bag chain. However, it
is preferred that the individual, partially formed
flexible packages be separated from one another at station
460.
CA 02412684 2002-11-25
--30- Attorney Docket No. 67343
With reference to FIGS. 26, 27 and 40a, the
serial succession of partly formed flexible packages is
driven in the machine direction by roller drive 458. As
mentioned, it is preferred that the web be driven in an
intermediate fashion ;o as to bring various parts of the
web into registry with the various work stations which
perform successive operations on a particular package
portion, as the package portion and the overall web are
advanced in a downstream or machine direction. Controls
for the web drive can take any number of conventional
forms. Although supplemental web drives could be
employed, it is generally preferred that the web drive 458
act alone in pulling the web past the folding station and
stations downstream. As can be seen with reference to
FIG. 26, a relatively small portion of the web is pushed
by web drive 458. The portion of the web has had a number
of sealing operations preformed on it and accordingly is
sufficiently stiff to accommodate the relatively short
distance pushing displacement to align the folded package
portions at downstream station 460.
With reference to FIG. 40a, a series of knives
462 are employed to sever the bag chain to separate the
empty, partially formed. flexible packages at the end of
the bag chain. Knives 462 are aligned so as to intersect
the diamond-shaped openings 324, forming opposed V-shaped
notches in side seal:, of adjacent flexible packages.
With reference to FIG. 39, for example, the
notches formed are identified by 210. It is generally
preferred that V-shaped notches be formed in both side
seals of the flexible packages. It is generally preferred
that the portions of the bag chain be supported prior to
the severing operation so as to maintain positional
control of the severed flexible packages. Any of a number
of conventional supports, such as vacuum operated suction
cups can be employed for the purpose. As illustrated in
CA 02412684 2002-11-25
-31- Attorney Docket No. 67343
FIGS. 40a, 40b the flexible packages are mechanically
secured between a moveable clamp member 462 and a fixed
clamp blade 464. The clamp blades are carried on a
shuttle member 466 moveable back and forth in the
direction of arrow A466. As indicated in FIG. 40b,
shuttle 466 moves a flexible package 200 toward a
turntable 1010 located at station 1000 provided for the
fill, seal and transfer operations to be formed on the
flexible package. After an individual flexible package
200 is separated from the web chain, the packages
conveying to turntable 1010 by shuttle 466 with the sides
of the flexible package being secured by clamping fingers
468 supported by turntable 1010.
Referring again to FIG. 26, upper suction cups
469 are diagrammatically illustrated as spanning a pair of
partially formed flexible packages. Preferably, a pair of
suction cups 469 are employed, on opposite sides the
flexible packages so that, by withdrawing the suction cups
away from one another, the upper ends of the flexible
packages are opened. Preferably, however, the upper ends
of individual flexible packages are opened by vacuum cups
482 carried on arms 484. Turntable 1010 is then indexed
to bring the flexiblÃ: packages to work station 490 where a
wedge-shaped mechanical opener 492 is inserted in the
flexible package in the mariner indicated in FIG. 50.
Referring additionally to FIG. 49, the wedge-shape member
492 includes an inlet 494 for an inert flushing gas.
Internal passageways connect the inlet 494 to a pair of
outlet openings 496. At station 480 interior portions of
the flexible packages are inflated in a gas flushing
operation. Any suitable gas mixture could be employed,
although it is generally preferred that an inert gas for
gettering or otherwise displacing oxygen is employed. The
separated, but incompletely formed, flexible packages are
CA 02412684 2002-11-25
32- Attorney Docket No. 67343
advanced to filling station 500 with indexing of turntable
1010.
With reference to FIGS. 41-44, filling is
carried out using conventional duck bill members 506. As
schematically indicated in FIG. 44, filling is carried out
between the mated fastener track and panel 404 with the
bottom end 508 of the duck bill member being positioned
at, or more preferably below flange 12. Referring to FIG.
43, a wide opening is provided by the duck bill
arrangement nested within the opening formed between the
zipper track and unjoined package panel. A relatively
large size opening provided allows manufacturers to pour
products into the flexible packages at relatively high
production line speeds, a feature attractive for mass
production. The bottom end of flange 12 is schematically
indicated in FIG. 44 as separated from panel 402. This
arrangement is shown only for illustrative purposes, it
being preferred that the bottom end of flange 12 be joined
to panel 402 to prevent product from backing up above the
peel seal. Positioning the bottom end of the filling
apparatus beneath the peel seal for prevention of unwanted
product backup.
Turning now to FIGS. 41 and 42, the duck bill
filling apparatus 506 preferably has an articulated clam
shell configuration. The bottom ends 508 of the clam
shell members are initially brought together so as to
facilitate penetration into the interior of the flexible
package. Once the filling apparatus is successfully
inserted into the package interior, the filling apparatus
is advanced until the lower ends 508 are plunged below the
lower end of flange 12. The clam shell members are then
opened in the manner indicated in FIG. 42 to allow product
520 to drop into the flexible package.
The turntable is then indexed to bring the
filled package to station 600 where the package is
CA 02412684 2002-11-25
--33- Attorney Docket No. 67343
flushed, and then closed. Referring to FIGS. 26 and 51,
initially to FIG. 51, a gas flushing probe 602 is inserted
in the open end of the filled package. Probe 602 is
hollow so as to direct a stream of flushing gas in the
direction of arrows A602, preferably, to displace oxygen
within the package interior. With filling and flushing of
the flexible package being completed, a final preparation
step before top sealing is performed. With reference to
FIG. 26, conventional, linear stretching apparatus using
movable clamps 468 bring the top ends of the package side
walls together. With indexing of turntable 1010, the
flexible packages are then advanced to top sealing station
700 where the top seals are formed. With reference to
FIGS. 45 and 46, three pairs of sealing bars are employed.
The uppermost pair of sealing bars, identified by 710 form
the upper seal of the shroud indicated at 714 in FIG. 47.
The intermediate pair of sealing tools
identified by 718 form the fusion seal. between portion 12b
of flange 12 and panel 404. In order to complete the
desired seal, the right-hand seal tool 718 is heated
whereas the left-hand seal tool 71.8 is either unheated or
cooled, to provide backup so that pressure can be
developed during the sealing operation.
Finally, the lower end 12c of flange 12 is
joined to panel 404 by a heated sealing tool 730 and a
cooperating unheated or cooled seal tool 732. The
resulting fusion seal is located laterally adjacent to the
peel seal described earlier with reference to flange
portion 12a.
Referring to FIGS. 26 and 52, turntable 1010 is
then indexed to bring the fully formed, filled and sealed
flexible packages to a transfer station 800 where the
flexible package is released by the clamping plates, so as
to drop onto a transfer conveyor 802.
CA 02412684 2002-11-25
-34- Attorney Docket No. 67343
A flexible package having a removable shroud
covering a slide fastener has been shown. However, it
should be readily apparent for those skilled in the art
that apparatus 300 can readily form, fill and seal
flexible packages, such as those illustrated above in FIG.
1, for example, which lack the shroud feature.
In addition to advantages described above with
reference to the apparatus and method of filling flexible
packages, it will be appreciated that the reclosable
fastener tracks remain engaged or mated in the closed
position throughout the forming, filling and sealing of
flexible packages constructed according to principles of
the present invention. This reduces the number of unit
operations which would otherwise be required to open and
reclose the fastener tracks. Further, the working
surfaces of the fastener tracks are not exposed to
product, dust and particles, which could interfere with
reliable mating of the fastener tracks, and the ability of
the slider member to move freely. As indicated, for
example, in FIG. 35 the longer flange is preferably
associated with the male fastener track 26. As seen
above, the longer flange, at its bottom end, forms a peel
seal with a package panel. The shorter flange, associated
with the female fastener track 28 is permanently joined to
the package panel at an early stage of operation. The
anchoring of the flange carrying the female track 28 onto
the side panel of the bag and the application of the
peelable seal on that same side panel of the bag,
associated with the male fastener track, provides a unique
insulation of the reclosable top the flexible package
during the filling and gas flushing. This construction
creates a laminar flow of the purging gas (preferably
nitrogen or carbon dioxide) that effectively sweeps
residual oxygen from the unfilled flexible package. As
those skilled in the art of packaging foods and other
CA 02412684 2002-11-25
-35- Attorney Docket No. 67343
products are aware, this feature of the invention is
oftentimes found essential to provide a modified
atmosphere for packaging, which preserves the freshness of
the product being packaged.
The drawings and the foregoing descriptions are
not intended to represent the only forms of the invention
in regard to the details of its construction and manner of
operation. Changes in form and in the proportion of
parts, as well as the subst.tution of equivalents, are
contemplated as circumstances may suggest or render
expedient; and although specific terms have been employed,
they are intended in a generic and descriptive sense only
and not for the purposes of limitation, the scope of the
invention being delineated by the following claims.
